#include<stdio.h>
#include<math.h>
int main(void)
{
  double a,b,c,area,perimeter,s;
  scanf("%lf%lf%lf",&a,&b,&c);
  if(a+b<=c||a+c<=b||b+c<=a)
  {
    printf("These sides do not correspond to a valid triangle");
  }
  else
  {
  perimeter=a+b+c;
  s=perimeter/2.0;
  area=sqrt(s*(s-a)*(s-b)*(s-c));
    printf("area = %.2f; perimeter = %.2f",area,perimeter);
  }
  return 0;
}
